Speaker
Description
Currently, a framework is required to examine the production method of a target nuclide while considering various boundary conditions based on nuclear reaction calculation codes and evaluated nuclear data libraries. To address this, we have developed a framework based on CCONE [1, 2], which had not been previously established. This framework enables the easy investigation of reactions that maximize the production cross-section or thick target yield [3] of the target nuclide. Furthermore, improvements of this framework enable yield calculations for incident particles with continuous energy distributions.
Tohoku University RARiS Mikamine site (hereafter RARiS-Mikamine) has been manufacturing and supplying the Auger-electron emitter $^{64}$Cu via the $\gamma+^{66}$Zn reaction. In contrast, the production yield of $^{64}$Cu exhibits significant variation among experimental days, making it difficult to say that a stable supply has been achieved. To identify the cause of this variability, we applied this framework to evaluate the $^{64}$Cu production yield.
Evaluating the $^{64}$Cu production yield at RARiS-Mikamine requires the bremsstrahlung spectrum and the $^{64}$Cu production cross-section (excitation function). The bremsstrahlung spectrum was obtained by reproducing the RARiS-Mikamine experimental setup and irradiating a Ta converter with an electron beam in the radiation transport code PHITS [4]. The excitation function was acquired from CCONE and evaluated nuclear data libraries, including JENDL-5 [5]. Based on past experiments and calculations using the framework and PHITS, it was found that the misalignment of the electron beam position and the thickness of the Ta converter significantly affect the $^{64}$Cu production yield. A comparison between the experimental and calculated $^{64}$Cu production yields, incorporating these findings, suggested that the calculation using the JEFF-3.3 [6] excitation function best reproduces the experimental values. Currently, we are investigating other potential factors that might influence the $^{64}$Cu production yield. Furthermore, manufacturing experiments for the Auger-electron emitter $^{77}$Br have begun at the Tohoku University RARiS Aobayama site, and preparations for the evaluation of the $^{77}$Br production yield are also underway.
References
[1] O. Iwamoto, “Development of a Comprehensive Code for Nuclear Data Evaluation, CCONE, and Validation Using Neutron-Induced Cross Sections for Uranium Isotopes”, J. Nucl. Sci. Technol. 44(5), (2007), pp. 687-697.
[2] O. Iwamoto, N. Iwamoto, S. Kunieda et al., “The CCONE Code System and its Application to Nuclear Data Evaluation for Fission and Other Reactions”, Nucl. Data Sheets 131, (2016), pp. 259-288.
[3] N. Otuka, S. Tak\'{a}cs, “Definitions of radioisotope thick target yields”, Radiochimica Acta 103(1), (2015), pp. 1-6.
[4] T. Sato, Y. Iwamoto, S. Hashimoto et al., “Recent improvements of the particle and heavy ion transport code system -- PHITS version 3.33”, J. Nucl. Sci. Technol. 61(1), (2024), pp. 127-135.
[5] O. Iwamoto, N. Iwamoto, S. Kunieda et al., “Japanese evaluated nuclear data library version 5: JENDL-5”, J. Nucl. Sci. Technol. 60(1), (2023), pp. 1-60.
[6] A. J. M. Plompen, O. Cabellos, C. De Saint Jean et al., “The joint evaluated fission and fusion nuclear data library, JEFF-3.3”, Eur. Phys. J. A 56:181, (2020), pp. 1-108.
